Portable battery



FIG. 1 is a front perspective view of a portable battery, showing my design.

FIG. 2 is a front elevation view thereof.

FIG. 3 is a rear elevation view thereof.

FIG. 4 is a left side elevation thereof.

FIG. 5 is a right side elevation thereof.

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a bottom plan view thereof.

Broken lines included in the drawings show portions of the portable battery that form no part of the claimed design. 

CLAIM The ornamental design for a portable battery, as shown and described. 